/*****************************************************************************
* ipcp.c - Network PPP IP Control Protocol program file.
*
* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
* portions Copyright (c) 1997 by Global Election Systems Inc.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice and the following disclaimer are included verbatim in any
* distributions. No written agreement, license, or royalty fee is required
* for any of the authorized uses.
*
* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
* REVISION HISTORY
*
* 03-01-01 Marc Boucher <marc@mbsi.ca>
*   Ported to lwIP.
* 97-12-08 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
*	Original.
*****************************************************************************/
/*
 * ipcp.c - PPP IP Control Protocol.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <string.h>

#include "ppp.h"
#if PPP_SUPPORT > 0
#include "auth.h"
#include "fsm.h"
#include "vj.h"
#include "ipcp.h"
#include "pppdebug.h"


/*************************/
/*** LOCAL DEFINITIONS ***/
/*************************/
/* #define OLD_CI_ADDRS 1 */	/* Support deprecated address negotiation. */

/*
 * Lengths of configuration options.
 */
#define CILEN_VOID	2
#define CILEN_COMPRESS	4	/* min length for compression protocol opt. */
#define CILEN_VJ	6	/* length for RFC1332 Van-Jacobson opt. */
#define CILEN_ADDR	6	/* new-style single address option */
#define CILEN_ADDRS	10	/* old-style dual address option */



/***********************************/
/*** LOCAL FUNCTION DECLARATIONS ***/
/***********************************/
/*
 * Callbacks for fsm code.  (CI = Configuration Information)
 */
static void ipcp_resetci (fsm *);	/* Reset our CI */
static int  ipcp_cilen (fsm *);	        /* Return length of our CI */
static void ipcp_addci (fsm *, u_char *, int *); /* Add our CI */
static int  ipcp_ackci (fsm *, u_char *, int);	/* Peer ack'd our CI */
static int  ipcp_nakci (fsm *, u_char *, int);	/* Peer nak'd our CI */
static int  ipcp_rejci (fsm *, u_char *, int);	/* Peer rej'd our CI */
static int  ipcp_reqci (fsm *, u_char *, int *, int); /* Rcv CI */
static void ipcp_up (fsm *);		/* We're UP */
static void ipcp_down (fsm *);		/* We're DOWN */
#if 0
static void ipcp_script (fsm *, char *); /* Run an up/down script */
#endif
static void ipcp_finished (fsm *);	/* Don't need lower layer */

/*
 * Protocol entry points from main code.
 */
static void ipcp_init (int);
static void ipcp_open (int);
static void ipcp_close (int, char *);
static void ipcp_lowerup (int);
static void ipcp_lowerdown (int);
static void ipcp_input (int, u_char *, int);
static void ipcp_protrej (int);

static void ipcp_clear_addrs (int);

#define CODENAME(x)	((x) == CONFACK ? "ACK" : \
			 (x) == CONFNAK ? "NAK" : "REJ")



/******************************/
/*** PUBLIC DATA STRUCTURES ***/
/******************************/
/* global vars */
ipcp_options ipcp_wantoptions[NUM_PPP];	/* Options that we want to request */
ipcp_options ipcp_gotoptions[NUM_PPP];	/* Options that peer ack'd */
ipcp_options ipcp_allowoptions[NUM_PPP];	/* Options we allow peer to request */
ipcp_options ipcp_hisoptions[NUM_PPP];	/* Options that we ack'd */

fsm ipcp_fsm[NUM_PPP];		/* IPCP fsm structure */

struct protent ipcp_protent =
        {
                PPP_IPCP,
                ipcp_init,
                ipcp_input,
                ipcp_protrej,
                ipcp_lowerup,
                ipcp_lowerdown,
                ipcp_open,
                ipcp_close,
#if 0
                ipcp_printpkt,
                NULL,
#endif
                1,
                "IPCP",
#if 0
                ip_check_options,
                NULL,
                ip_active_pkt
#endif
        };



/*****************************/
/*** LOCAL DATA STRUCTURES ***/
/*****************************/
/* local vars */
static int cis_received[NUM_PPP];		/* # Conf-Reqs received */
static int default_route_set[NUM_PPP];	/* Have set up a default route */

static fsm_callbacks ipcp_callbacks =
        { /* IPCP callback routines */
                ipcp_resetci,		/* Reset our Configuration Information */
                ipcp_cilen,			/* Length of our Configuration Information */
                ipcp_addci,			/* Add our Configuration Information */
                ipcp_ackci,			/* ACK our Configuration Information */
                ipcp_nakci,			/* NAK our Configuration Information */
                ipcp_rejci,			/* Reject our Configuration Information */
                ipcp_reqci,			/* Request peer's Configuration Information */
                ipcp_up,			/* Called when fsm reaches OPENED state */
                ipcp_down,			/* Called when fsm leaves OPENED state */
                NULL,				/* Called when we want the lower layer up */
                ipcp_finished,		/* Called when we want the lower layer down */
                NULL,				/* Called when Protocol-Reject received */
                NULL,				/* Retransmission is necessary */
                NULL,				/* Called to handle protocol-specific codes */
                "IPCP"				/* String name of protocol */
        };



/**********************************/
/*** LOCAL FUNCTION DEFINITIONS ***/
/**********************************/

/*
 * Non-standard inet_ntoa left here for compat with original ppp
 * sources. Assumes u32_t instead of struct in_addr.
 */

char * _inet_ntoa(u32_t n)
{
        struct in_addr ia;
        ia.s_addr = n;
        return inet_ntoa(ia);
}

#define inet_ntoa _inet_ntoa

/*
 * ipcp_init - Initialize IPCP.
 */
static void ipcp_init(int unit)
{
        fsm *f = &ipcp_fsm[unit];
        ipcp_options *wo = &ipcp_wantoptions[unit];
        ipcp_options *ao = &ipcp_allowoptions[unit];

        f->unit = unit;
        f->protocol = PPP_IPCP;
        f->callbacks = &ipcp_callbacks;
        fsm_init(&ipcp_fsm[unit]);

        memset(wo, 0, sizeof(*wo));
        memset(ao, 0, sizeof(*ao));

        wo->neg_addr = 1;
        wo->ouraddr = 0;
#if VJ_SUPPORT > 0
        wo->neg_vj = 1;
#else
        wo->neg_vj = 0;
#endif
        wo->vj_protocol = IPCP_VJ_COMP;
        wo->maxslotindex = MAX_SLOTS - 1;
        wo->cflag = 0;

        wo->default_route = 1;

        ao->neg_addr = 1;
#if VJ_SUPPORT > 0
        ao->neg_vj = 1;
#else
        ao->neg_vj = 0;
#endif
        ao->maxslotindex = MAX_SLOTS - 1;
        ao->cflag = 1;

        ao->default_route = 1;
}


/*
 * ipcp_open - IPCP is allowed to come up.
 */
static void ipcp_open(int unit)
{
        fsm_open(&ipcp_fsm[unit]);
}


/*
 * ipcp_close - Take IPCP down.
 */
static void ipcp_close(int unit, char *reason)
{
        fsm_close(&ipcp_fsm[unit], reason);
}


/*
 * ipcp_lowerup - The lower layer is up.
 */
static void ipcp_lowerup(int unit)
{
        fsm_lowerup(&ipcp_fsm[unit]);
}


/*
 * ipcp_lowerdown - The lower layer is down.
 */
static void ipcp_lowerdown(int unit)
{
        fsm_lowerdown(&ipcp_fsm[unit]);
}


/*
 * ipcp_input - Input IPCP packet.
 */
static void ipcp_input(int unit, u_char *p, int len)
{
        fsm_input(&ipcp_fsm[unit], p, len);
}


/*
 * ipcp_protrej - A Protocol-Reject was received for IPCP.
 *
 * Pretend the lower layer went down, so we shut up.
 */
static void ipcp_protrej(int unit)
{
        fsm_lowerdown(&ipcp_fsm[unit]);
}


/*
 * ipcp_resetci - Reset our CI.
 */
static void ipcp_resetci(fsm *f)
{
        ipcp_options *wo = &ipcp_wantoptions[f->unit];

        wo->req_addr = wo->neg_addr && ipcp_allowoptions[f->unit].neg_addr;
        if (wo->ouraddr == 0)
                wo->accept_local = 1;
        if (wo->hisaddr == 0)
                wo->accept_remote = 1;
        /* Request DNS addresses from the peer */
        wo->req_dns1 = ppp_settings.usepeerdns;
        wo->req_dns2 = ppp_settings.usepeerdns;
        ipcp_gotoptions[f->unit] = *wo;
        cis_received[f->unit] = 0;
}


/*
 * ipcp_cilen - Return length of our CI.
 */
static int ipcp_cilen(fsm *f)
{
        ipcp_options *go = &ipcp_gotoptions[f->unit];
        ipcp_options *wo = &ipcp_wantoptions[f->unit];
        ipcp_options *ho = &ipcp_hisoptions[f->unit];

#define LENCIVJ(neg, old)	(neg ? (old? CILEN_COMPRESS : CILEN_VJ) : 0)
#define LENCIADDR(neg, old)	(neg ? (old? CILEN_ADDRS : CILEN_ADDR) : 0)
#define LENCIDNS(neg)		(neg ? (CILEN_ADDR) : 0)

        /*
         * First see if we want to change our options to the old
         * forms because we have received old forms from the peer.
         */
        if (wo->neg_addr && !go->neg_addr && !go->old_addrs) {
                /* use the old style of address negotiation */
                go->neg_addr = 1;
                go->old_addrs = 1;
        }
        if (wo->neg_vj && !go->neg_vj && !go->old_vj) {
                /* try an older style of VJ negotiation */
                if (cis_received[f->unit] == 0) {
                        /* keep trying the new style until we see some CI from the peer */
                        go->neg_vj = 1;
                } else {
                        /* use the old style only if the peer did */
                        if (ho->neg_vj && ho->old_vj) {
                                go->neg_vj = 1;
                                go->old_vj = 1;
                                go->vj_protocol = ho->vj_protocol;
                        }
                }
        }

        return (LENCIADDR(go->neg_addr, go->old_addrs)
                + LENCIVJ(go->neg_vj, go->old_vj) +
                LENCIDNS(go->req_dns1) +
                LENCIDNS(go->req_dns2));
}


/*
 * ipcp_addci - Add our desired CIs to a packet.
 */
static void ipcp_addci(fsm *f, u_char *ucp, int *lenp)
{
        ipcp_options *go = &ipcp_gotoptions[f->unit];
        int len = *lenp;

#define ADDCIVJ(opt, neg, val, old, maxslotindex, cflag) \
	if (neg) { \
		int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
		if (len >= vjlen) { \
			PUTCHAR(opt, ucp); \
			PUTCHAR(vjlen, ucp); \
			PUTSHORT(val, ucp); \
			if (!old) { \
				PUTCHAR(maxslotindex, ucp); \
				PUTCHAR(cflag, ucp); \
			} \
			len -= vjlen; \
		} else \
			neg = 0; \
	}

#define ADDCIADDR(opt, neg, old, val1, val2) \
	if (neg) { \
		int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \
		if (len >= addrlen) { \
			u32_t l; \
			PUTCHAR(opt, ucp); \
			PUTCHAR(addrlen, ucp); \
			l = ntohl(val1); \
			PUTLONG(l, ucp); \
			if (old) { \
				l = ntohl(val2); \
				PUTLONG(l, ucp); \
			} \
			len -= addrlen; \
		} else \
			neg = 0; \
	}

#define ADDCIDNS(opt, neg, addr) \
	if (neg) { \
		if (len >= CILEN_ADDR) { \
			u32_t l; \
			PUTCHAR(opt, ucp); \
			PUTCHAR(CILEN_ADDR, ucp); \
			l = ntohl(addr); \
			PUTLONG(l, ucp); \
			len -= CILEN_ADDR; \
		} else \
			neg = 0; \
	}

        ADDCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr,
                  go->old_addrs, go->ouraddr, go->hisaddr);

        ADDCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
                go->maxslotindex, go->cflag);

        ADDCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);

        ADDCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);

        *lenp -= len;
}


/*
 * ipcp_ackci - Ack our CIs.
 *
 * Returns:
 *	0 - Ack was bad.
 *	1 - Ack was good.
 */
static int ipcp_ackci(fsm *f, u_char *p, int len)
{
        ipcp_options *go = &ipcp_gotoptions[f->unit];
        u_short cilen, citype, cishort;
        u32_t cilong;
        u_char cimaxslotindex, cicflag;

        /*
         * CIs must be in exactly the same order that we sent...
         * Check packet length and CI length at each step.
         * If we find any deviations, then this packet is bad.
         */

#define ACKCIVJ(opt, neg, val, old, maxslotindex, cflag) \
	if (neg) { \
		int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \
		if ((len -= vjlen) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != vjlen || \
				citype != opt)  \
			goto bad; \
		GETSHORT(cishort, p); \
		if (cishort != val) \
			goto bad; \
		if (!old) { \
			GETCHAR(cimaxslotindex, p); \
			if (cimaxslotindex != maxslotindex) \
				goto bad; \
			GETCHAR(cicflag, p); \
			if (cicflag != cflag) \
				goto bad; \
		} \
	}

#define ACKCIADDR(opt, neg, old, val1, val2) \
	if (neg) { \
		int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \
		u32_t l; \
		if ((len -= addrlen) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != addrlen || \
				citype != opt) \
			goto bad; \
		GETLONG(l, p); \
		cilong = htonl(l); \
		if (val1 != cilong) \
			goto bad; \
		if (old) { \
			GETLONG(l, p); \
			cilong = htonl(l); \
			if (val2 != cilong) \
				goto bad; \
		} \
	}

#define ACKCIDNS(opt, neg, addr) \
	if (neg) { \
		u32_t l; \
		if ((len -= CILEN_ADDR) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != CILEN_ADDR || \
				citype != opt) \
			goto bad; \
		GETLONG(l, p); \
		cilong = htonl(l); \
		if (addr != cilong) \
			goto bad; \
	}

        ACKCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr,
                  go->old_addrs, go->ouraddr, go->hisaddr);

        ACKCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
                go->maxslotindex, go->cflag);

        ACKCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);

        ACKCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);

        /*
         * If there are any remaining CIs, then this packet is bad.
         */
        if (len != 0)
                goto bad;
        return (1);

bad:
        IPCPDEBUG((LOG_INFO, "ipcp_ackci: received bad Ack!\n"));
        return (0);
}

/*
 * ipcp_nakci - Peer has sent a NAK for some of our CIs.
 * This should not modify any state if the Nak is bad
 * or if IPCP is in the OPENED state.
 *
 * Returns:
 *	0 - Nak was bad.
 *	1 - Nak was good.
 */
static int ipcp_nakci(fsm *f, u_char *p, int len)
{
        ipcp_options *go = &ipcp_gotoptions[f->unit];
        u_char cimaxslotindex, cicflag;
        u_char citype, cilen, *next;
        u_short cishort;
        u32_t ciaddr1, ciaddr2, l, cidnsaddr;
        ipcp_options no;		/* options we've seen Naks for */
        ipcp_options try;		/* options to request next time */

        BZERO(&no, sizeof(no));
        try = *go;

        /*
         * Any Nak'd CIs must be in exactly the same order that we sent.
         * Check packet length and CI length at each step.
         * If we find any deviations, then this packet is bad.
         */
#define NAKCIADDR(opt, neg, old, code) \
	if (go->neg && \
			len >= (cilen = (old? CILEN_ADDRS: CILEN_ADDR)) && \
			p[1] == cilen && \
			p[0] == opt) { \
		len -= cilen; \
		INCPTR(2, p); \
		GETLONG(l, p); \
		ciaddr1 = htonl(l); \
		if (old) { \
			GETLONG(l, p); \
			ciaddr2 = htonl(l); \
			no.old_addrs = 1; \
		} else \
			ciaddr2 = 0; \
		no.neg = 1; \
		code \
	}

#define NAKCIVJ(opt, neg, code) \
	if (go->neg && \
			((cilen = p[1]) == CILEN_COMPRESS || cilen == CILEN_VJ) && \
			len >= cilen && \
			p[0] == opt) { \
		len -= cilen; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
		no.neg = 1; \
		code \
	}

#define NAKCIDNS(opt, neg, code) \
	if (go->neg && \
			((cilen = p[1]) == CILEN_ADDR) && \
			len >= cilen && \
			p[0] == opt) { \
		len -= cilen; \
		INCPTR(2, p); \
		GETLONG(l, p); \
		cidnsaddr = htonl(l); \
		no.neg = 1; \
		code \
	}

        /*
         * Accept the peer's idea of {our,his} address, if different
         * from our idea, only if the accept_{local,remote} flag is set.
         */
        NAKCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr, go->old_addrs,
                  if (go->accept_local && ciaddr1) { /* Do we know our address? */
                  try.ouraddr = ciaddr1;
                  IPCPDEBUG((LOG_INFO, "local IP address %s\n",
                             inet_ntoa(ciaddr1)));
                  }
                  if (go->accept_remote && ciaddr2) { /* Does he know his? */
                  try.hisaddr = ciaddr2;
                  IPCPDEBUG((LOG_INFO, "remote IP address %s\n",
                             inet_ntoa(ciaddr2)));
                  }
                 );

        /*
         * Accept the peer's value of maxslotindex provided that it
         * is less than what we asked for.  Turn off slot-ID compression
         * if the peer wants.  Send old-style compress-type option if
         * the peer wants.
         */
        NAKCIVJ(CI_COMPRESSTYPE, neg_vj,
                if (cilen == CILEN_VJ) {
                GETCHAR(cimaxslotindex, p);
                        GETCHAR(cicflag, p);
                        if (cishort == IPCP_VJ_COMP) {
                                try.old_vj = 0;
                                if (cimaxslotindex < go->maxslotindex)
                                        try.maxslotindex = cimaxslotindex;
                                if (!cicflag)
                                        try.cflag = 0;
                        } else {
                                try.neg_vj = 0;
                        }
                } else {
                        if (cishort == IPCP_VJ_COMP || cishort == IPCP_VJ_COMP_OLD) {
                                try.old_vj = 1;
                                try.vj_protocol = cishort;
                        } else {
                                try.neg_vj = 0;
                        }
                }
               );

        NAKCIDNS(CI_MS_DNS1, req_dns1,
                 try.dnsaddr[0] = cidnsaddr;
                 IPCPDEBUG((LOG_INFO, "primary DNS address %s\n", inet_ntoa(cidnsaddr)));
                );

        NAKCIDNS(CI_MS_DNS2, req_dns2,
                 try.dnsaddr[1] = cidnsaddr;
                 IPCPDEBUG((LOG_INFO, "secondary DNS address %s\n", inet_ntoa(cidnsaddr)));
                );

        /*
        * There may be remaining CIs, if the peer is requesting negotiation
        * on an option that we didn't include in our request packet.
        * If they want to negotiate about IP addresses, we comply.
        * If they want us to ask for compression, we refuse.
        */
        while (len > CILEN_VOID) {
                GETCHAR(citype, p);
                GETCHAR(cilen, p);
                if ( (len -= cilen) < 0 )
                        goto bad;
                next = p + cilen - 2;

                switch (citype) {
                case CI_COMPRESSTYPE:
                        if (go->neg_vj || no.neg_vj ||
                                        (cilen != CILEN_VJ && cilen != CILEN_COMPRESS))
                                goto bad;
                        no.neg_vj = 1;
                        break;
                case CI_ADDRS:
                        if ((go->neg_addr && go->old_addrs) || no.old_addrs
                                        || cilen != CILEN_ADDRS)
                                goto bad;
                        try.neg_addr = 1;
                        try.old_addrs = 1;
                        GETLONG(l, p);
                        ciaddr1 = htonl(l);
                        if (ciaddr1 && go->accept_local)
                                try.ouraddr = ciaddr1;
                        GETLONG(l, p);
                        ciaddr2 = htonl(l);
                        if (ciaddr2 && go->accept_remote)
                                try.hisaddr = ciaddr2;
                        no.old_addrs = 1;
                        break;
                case CI_ADDR:
                        if (go->neg_addr || no.neg_addr || cilen != CILEN_ADDR)
                                goto bad;
                        try.old_addrs = 0;
                        GETLONG(l, p);
                        ciaddr1 = htonl(l);
                        if (ciaddr1 && go->accept_local)
                                try.ouraddr = ciaddr1;
                        if (try.ouraddr != 0)
                                try.neg_addr = 1;
                        no.neg_addr = 1;
                        break;
                }
                p = next;
        }

        /* If there is still anything left, this packet is bad. */
        if (len != 0)
                goto bad;

        /*
         * OK, the Nak is good.  Now we can update state.
         */
        if (f->state != OPENED)
                *go = try;

        return 1;

bad:
        IPCPDEBUG((LOG_INFO, "ipcp_nakci: received bad Nak!\n"));
        return 0;
}


/*
 * ipcp_rejci - Reject some of our CIs.
 */
static int ipcp_rejci(fsm *f, u_char *p, int len)
{
        ipcp_options *go = &ipcp_gotoptions[f->unit];
        u_char cimaxslotindex, ciflag, cilen;
        u_short cishort;
        u32_t cilong;
        ipcp_options try;		/* options to request next time */

        try = *go;
        /*
         * Any Rejected CIs must be in exactly the same order that we sent.
         * Check packet length and CI length at each step.
         * If we find any deviations, then this packet is bad.
         */
#define REJCIADDR(opt, neg, old, val1, val2) \
	if (go->neg && \
			len >= (cilen = old? CILEN_ADDRS: CILEN_ADDR) && \
			p[1] == cilen && \
			p[0] == opt) { \
		u32_t l; \
		len -= cilen; \
		INCPTR(2, p); \
		GETLONG(l, p); \
		cilong = htonl(l); \
		/* Check rejected value. */ \
		if (cilong != val1) \
			goto bad; \
		if (old) { \
			GETLONG(l, p); \
			cilong = htonl(l); \
			/* Check rejected value. */ \
			if (cilong != val2) \
				goto bad; \
		} \
		try.neg = 0; \
	}

#define REJCIVJ(opt, neg, val, old, maxslot, cflag) \
	if (go->neg && \
			p[1] == (old? CILEN_COMPRESS : CILEN_VJ) && \
			len >= p[1] && \
			p[0] == opt) { \
		len -= p[1]; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
		/* Check rejected value. */  \
		if (cishort != val) \
			goto bad; \
		if (!old) { \
			GETCHAR(cimaxslotindex, p); \
			if (cimaxslotindex != maxslot) \
				goto bad; \
			GETCHAR(ciflag, p); \
			if (ciflag != cflag) \
				goto bad; \
		} \
		try.neg = 0; \
	}

#define REJCIDNS(opt, neg, dnsaddr) \
	if (go->neg && \
			((cilen = p[1]) == CILEN_ADDR) && \
			len >= cilen && \
			p[0] == opt) { \
		u32_t l; \
		len -= cilen; \
		INCPTR(2, p); \
		GETLONG(l, p); \
		cilong = htonl(l); \
		/* Check rejected value. */ \
		if (cilong != dnsaddr) \
			goto bad; \
		try.neg = 0; \
	}

        REJCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr,
                  go->old_addrs, go->ouraddr, go->hisaddr);

        REJCIVJ(CI_COMPRESSTYPE, neg_vj, go->vj_protocol, go->old_vj,
                go->maxslotindex, go->cflag);

        REJCIDNS(CI_MS_DNS1, req_dns1, go->dnsaddr[0]);

        REJCIDNS(CI_MS_DNS2, req_dns2, go->dnsaddr[1]);

        /*
         * If there are any remaining CIs, then this packet is bad.
         */
        if (len != 0)
                goto bad;
        /*
         * Now we can update state.
         */
        if (f->state != OPENED)
                *go = try;
        return 1;

bad:
        IPCPDEBUG((LOG_INFO, "ipcp_rejci: received bad Reject!\n"));
        return 0;
}


/*
 * ipcp_reqci - Check the peer's requested CIs and send appropriate response.
 *
 * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
 * appropriately.  If reject_if_disagree is non-zero, doesn't return
 * CONFNAK; returns CONFREJ if it can't return CONFACK.
 */
static int ipcp_reqci(
        fsm *f,
        u_char *inp,		/* Requested CIs */
        int *len,			/* Length of requested CIs */
        int reject_if_disagree
)
{
        ipcp_options *wo = &ipcp_wantoptions[f->unit];
        ipcp_options *ho = &ipcp_hisoptions[f->unit];
        ipcp_options *ao = &ipcp_allowoptions[f->unit];
#ifdef OLD_CI_ADDRS
        ipcp_options *go = &ipcp_gotoptions[f->unit];
#endif
        u_char *cip, *next;				/* Pointer to current and next CIs */
        u_short cilen, citype;			/* Parsed len, type */
        u_short cishort;				/* Parsed short value */
        u32_t tl, ciaddr1;			/* Parsed address values */
#ifdef OLD_CI_ADDRS
        u32_t ciaddr2;				/* Parsed address values */
#endif
        int rc = CONFACK;				/* Final packet return code */
        int orc;						/* Individual option return code */
        u_char *p;						/* Pointer to next char to parse */
        u_char *ucp = inp;				/* Pointer to current output char */
        int l = *len;					/* Length left */
        u_char maxslotindex, cflag;
        int d;

        cis_received[f->unit] = 1;

        /*
         * Reset all his options.
         */
        BZERO(ho, sizeof(*ho));

        /*
         * Process all his options.
         */
        next = inp;
        while (l) {
                orc = CONFACK;				/* Assume success */
                cip = p = next;				/* Remember begining of CI */
                if (l < 2 ||				/* Not enough data for CI header or */
                                p[1] < 2 ||			/*  CI length too small or */
                                p[1] > l) {			/*  CI length too big? */
                        IPCPDEBUG((LOG_INFO, "ipcp_reqci: bad CI length!\n"));
                        orc = CONFREJ;			/* Reject bad CI */
                        cilen = l;				/* Reject till end of packet */
                        l = 0;					/* Don't loop again */
                        goto endswitch;
                }
                GETCHAR(citype, p);			/* Parse CI type */
                GETCHAR(cilen, p);			/* Parse CI length */
                l -= cilen;					/* Adjust remaining length */
                next += cilen;				/* Step to next CI */

                switch (citype) {			/* Check CI type */
#ifdef OLD_CI_ADDRS /* Need to save space... */
                case CI_ADDRS:
                        IPCPDEBUG((LOG_INFO, "ipcp_reqci: received ADDRS\n"));
                        if (!ao->neg_addr ||
                                        cilen != CILEN_ADDRS) {	/* Check CI length */
                                orc = CONFREJ;		/* Reject CI */
                                break;
                        }

                        /*
                         * If he has no address, or if we both have his address but
                         * disagree about it, then NAK it with our idea.
                         * In particular, if we don't know his address, but he does,
                         * then accept it.
                         */
                        GETLONG(tl, p);		/* Parse source address (his) */
                        ciaddr1 = htonl(tl);
                        IPCPDEBUG((LOG_INFO, "his addr %s\n", inet_ntoa(ciaddr1)));
                        if (ciaddr1 != wo->hisaddr
                                        && (ciaddr1 == 0 || !wo->accept_remote)) {
                                orc = CONFNAK;
                                if (!reject_if_disagree) {
                                        DECPTR(sizeof(u32_t), p);
                                        tl = ntohl(wo->hisaddr);
                                        PUTLONG(tl, p);
                                }
                        } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
                                /*
                                 * If neither we nor he knows his address, reject the option.
                                 */
                                orc = CONFREJ;
                                wo->req_addr = 0;	/* don't NAK with 0.0.0.0 later */
                                break;
                        }

                        /*
                         * If he doesn't know our address, or if we both have our address
                         * but disagree about it, then NAK it with our idea.
                         */
                        GETLONG(tl, p);		/* Parse desination address (ours) */
                        ciaddr2 = htonl(tl);
                        IPCPDEBUG((LOG_INFO, "our addr %s\n", inet_ntoa(ciaddr2)));
                        if (ciaddr2 != wo->ouraddr) {
                                if (ciaddr2 == 0 || !wo->accept_local) {
                                        orc = CONFNAK;
                                        if (!reject_if_disagree) {
                                                DECPTR(sizeof(u32_t), p);
                                                tl = ntohl(wo->ouraddr);
                                                PUTLONG(tl, p);
                                        }
                                } else {
                                        go->ouraddr = ciaddr2;	/* accept peer's idea */
                                }
                        }

                        ho->neg_addr = 1;
                        ho->old_addrs = 1;
                        ho->hisaddr = ciaddr1;
                        ho->ouraddr = ciaddr2;
                        break;
#endif

                case CI_ADDR:
                        if (!ao->neg_addr) {
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Reject ADDR not allowed\n"));
                                orc = CONFREJ;				/* Reject CI */
                                break;
                        } else if (cilen != CILEN_ADDR) {	/* Check CI length */
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Reject ADDR bad len\n"));
                                orc = CONFREJ;				/* Reject CI */
                                break;
                        }

                        /*
                         * If he has no address, or if we both have his address but
                         * disagree about it, then NAK it with our idea.
                         * In particular, if we don't know his address, but he does,
                         * then accept it.
                         */
                        GETLONG(tl, p);	/* Parse source address (his) */
                        ciaddr1 = htonl(tl);
                        if (ciaddr1 != wo->hisaddr
                                        && (ciaddr1 == 0 || !wo->accept_remote)) {
                                orc = CONFNAK;
                                if (!reject_if_disagree) {
                                        DECPTR(sizeof(u32_t), p);
                                        tl = ntohl(wo->hisaddr);
                                        PUTLONG(tl, p);
                                }
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Nak ADDR %s\n", inet_ntoa(ciaddr1)));
                        } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
                                /*
                                 * Don't ACK an address of 0.0.0.0 - reject it instead.
                                 */
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Reject ADDR %s\n", inet_ntoa(ciaddr1)));
                                orc = CONFREJ;
                                wo->req_addr = 0;	/* don't NAK with 0.0.0.0 later */
                                break;
                        }

                        ho->neg_addr = 1;
                        ho->hisaddr = ciaddr1;
                        IPCPDEBUG((LOG_INFO, "ipcp_reqci: ADDR %s\n", inet_ntoa(ciaddr1)));
                        break;

                case CI_MS_DNS1:
                case CI_MS_DNS2:
                        /* Microsoft primary or secondary DNS request */
                        d = citype == CI_MS_DNS2;

                        /* If we do not have a DNS address then we cannot send it */
                        if (ao->dnsaddr[d] == 0 ||
                                        cilen != CILEN_ADDR) {	/* Check CI length */
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Rejecting DNS%d Request\n", d+1));
                                orc = CONFREJ;				/* Reject CI */
                                break;
                        }
                        GETLONG(tl, p);
                        if (htonl(tl) != ao->dnsaddr[d]) {
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Naking DNS%d Request %d\n",
                                           d+1, inet_ntoa(tl)));
                                DECPTR(sizeof(u32_t), p);
                                tl = ntohl(ao->dnsaddr[d]);
                                PUTLONG(tl, p);
                                orc = CONFNAK;
                        }
                        IPCPDEBUG((LOG_INFO, "ipcp_reqci: received DNS%d Request\n", d+1));
                        break;

                case CI_MS_WINS1:
                case CI_MS_WINS2:
                        /* Microsoft primary or secondary WINS request */
                        d = citype == CI_MS_WINS2;
                        IPCPDEBUG((LOG_INFO, "ipcp_reqci: received WINS%d Request\n", d+1));

                        /* If we do not have a DNS address then we cannot send it */
                        if (ao->winsaddr[d] == 0 ||
                                        cilen != CILEN_ADDR) {	/* Check CI length */
                                orc = CONFREJ;			/* Reject CI */
                                break;
                        }
                        GETLONG(tl, p);
                        if (htonl(tl) != ao->winsaddr[d]) {
                                DECPTR(sizeof(u32_t), p);
                                tl = ntohl(ao->winsaddr[d]);
                                PUTLONG(tl, p);
                                orc = CONFNAK;
                        }
                        break;

                case CI_COMPRESSTYPE:
                        if (!ao->neg_vj) {
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Rejecting COMPRESSTYPE not allowed\n"));
                                orc = CONFREJ;
                                break;
                        } else if (cilen != CILEN_VJ && cilen != CILEN_COMPRESS) {
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Rejecting COMPRESSTYPE len=%d\n", cilen));
                                orc = CONFREJ;
                                break;
                        }
                        GETSHORT(cishort, p);

                        if (!(cishort == IPCP_VJ_COMP ||
                                        (cishort == IPCP_VJ_COMP_OLD && cilen == CILEN_COMPRESS))) {
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Rejecting COMPRESSTYPE %d\n", cishort));
                                orc = CONFREJ;
                                break;
                        }

                        ho->neg_vj = 1;
                        ho->vj_protocol = cishort;
                        if (cilen == CILEN_VJ) {
                                GETCHAR(maxslotindex, p);
                                if (maxslotindex > ao->maxslotindex) {
                                        IPCPDEBUG((LOG_INFO, "ipcp_reqci: Naking VJ max slot %d\n", maxslotindex));
                                        orc = CONFNAK;
                                        if (!reject_if_disagree) {
                                                DECPTR(1, p);
                                                PUTCHAR(ao->maxslotindex, p);
                                        }
                                }
                                GETCHAR(cflag, p);
                                if (cflag && !ao->cflag) {
                                        IPCPDEBUG((LOG_INFO, "ipcp_reqci: Naking VJ cflag %d\n", cflag));
                                        orc = CONFNAK;
                                        if (!reject_if_disagree) {
                                                DECPTR(1, p);
                                                PUTCHAR(wo->cflag, p);
                                        }
                                }
                                ho->maxslotindex = maxslotindex;
                                ho->cflag = cflag;
                        } else {
                                ho->old_vj = 1;
                                ho->maxslotindex = MAX_SLOTS - 1;
                                ho->cflag = 1;
                        }
                        IPCPDEBUG((LOG_INFO,
                                   "ipcp_reqci: received COMPRESSTYPE p=%d old=%d maxslot=%d cflag=%d\n",
                                   ho->vj_protocol, ho->old_vj, ho->maxslotindex, ho->cflag));
                        break;

                default:
                        IPCPDEBUG((LOG_INFO, "ipcp_reqci: Rejecting unknown CI type %d\n", citype));
                        orc = CONFREJ;
                        break;
                }

endswitch:
                if (orc == CONFACK &&		/* Good CI */
                                rc != CONFACK)		/*  but prior CI wasnt? */
                        continue;				/* Don't send this one */

                if (orc == CONFNAK) {		/* Nak this CI? */
                        if (reject_if_disagree) {	/* Getting fed up with sending NAKs? */
                                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Rejecting too many naks\n"));
                                orc = CONFREJ;		/* Get tough if so */
                        } else {
                                if (rc == CONFREJ)	/* Rejecting prior CI? */
                                        continue;		/* Don't send this one */
                                if (rc == CONFACK) {	/* Ack'd all prior CIs? */
                                        rc = CONFNAK;	/* Not anymore... */
                                        ucp = inp;		/* Backup */
                                }
                        }
                }

                if (orc == CONFREJ &&		/* Reject this CI */
                                rc != CONFREJ) {	/*  but no prior ones? */
                        rc = CONFREJ;
                        ucp = inp;				/* Backup */
                }

                /* Need to move CI? */
                if (ucp != cip)
                        BCOPY(cip, ucp, cilen);	/* Move it */

                /* Update output pointer */
                INCPTR(cilen, ucp);
        }

        /*
         * If we aren't rejecting this packet, and we want to negotiate
         * their address, and they didn't send their address, then we
         * send a NAK with a CI_ADDR option appended.  We assume the
         * input buffer is long enough that we can append the extra
         * option safely.
         */
        if (rc != CONFREJ && !ho->neg_addr &&
                        wo->req_addr && !reject_if_disagree) {
                IPCPDEBUG((LOG_INFO, "ipcp_reqci: Requesting peer address\n"));
                if (rc == CONFACK) {
                        rc = CONFNAK;
                        ucp = inp;				/* reset pointer */
                        wo->req_addr = 0;		/* don't ask again */
                }
                PUTCHAR(CI_ADDR, ucp);
                PUTCHAR(CILEN_ADDR, ucp);
                tl = ntohl(wo->hisaddr);
                PUTLONG(tl, ucp);
        }

        *len = (int)(ucp - inp);		/* Compute output length */
        IPCPDEBUG((LOG_INFO, "ipcp_reqci: returning Configure-%s\n", CODENAME(rc)));
        return (rc);			/* Return final code */
}


#if 0
/*
 * ip_check_options - check that any IP-related options are OK,
 * and assign appropriate defaults.
 */
static void ip_check_options(u_long localAddr)
{
        ipcp_options *wo = &ipcp_wantoptions[0];

        /*
         * Load our default IP address but allow the remote host to give us
         * a new address.
         */
        if (wo->ouraddr == 0 && !ppp_settings.disable_defaultip) {
                wo->accept_local = 1;	/* don't insist on this default value */
                wo->ouraddr = htonl(localAddr);
        }
}
#endif


/*
 * ipcp_up - IPCP has come UP.
 *
 * Configure the IP network interface appropriately and bring it up.
 */
static void ipcp_up(fsm *f)
{
        u32_t mask;
        ipcp_options *ho = &ipcp_hisoptions[f->unit];
        ipcp_options *go = &ipcp_gotoptions[f->unit];
        ipcp_options *wo = &ipcp_wantoptions[f->unit];

        np_up(f->unit, PPP_IP);
        IPCPDEBUG((LOG_INFO, "ipcp: up\n"));

        /*
         * We must have a non-zero IP address for both ends of the link.
         */
        if (!ho->neg_addr)
                ho->hisaddr = wo->hisaddr;

        if (ho->hisaddr == 0) {
                IPCPDEBUG((LOG_ERR, "Could not determine remote IP address\n"));
                ipcp_close(f->unit, "Could not determine remote IP address");
                return;
        }
        if (go->ouraddr == 0) {
                IPCPDEBUG((LOG_ERR, "Could not determine local IP address\n"));
                ipcp_close(f->unit, "Could not determine local IP address");
                return;
        }

        if (ppp_settings.usepeerdns && (go->dnsaddr[0] || go->dnsaddr[1])) {
                /*pppGotDNSAddrs(go->dnsaddr[0], go->dnsaddr[1]);*/
        }

        /*
         * Check that the peer is allowed to use the IP address it wants.
         */
        if (!auth_ip_addr(f->unit, ho->hisaddr)) {
                IPCPDEBUG((LOG_ERR, "Peer is not authorized to use remote address %s\n",
                           inet_ntoa(ho->hisaddr)));
                ipcp_close(f->unit, "Unauthorized remote IP address");
                return;
        }

        /* set tcp compression */
        sifvjcomp(f->unit, ho->neg_vj, ho->cflag, ho->maxslotindex);

        /*
         * Set IP addresses and (if specified) netmask.
         */
        mask = GetMask(go->ouraddr);

        if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask, go->dnsaddr[0], go->dnsaddr[1])) {
                IPCPDEBUG((LOG_WARNING, "sifaddr failed\n"));
                ipcp_close(f->unit, "Interface configuration failed");
                return;
        }

        /* bring the interface up for IP */
        if (!sifup(f->unit)) {
                IPCPDEBUG((LOG_WARNING, "sifup failed\n"));
                ipcp_close(f->unit, "Interface configuration failed");
                return;
        }

        sifnpmode(f->unit, PPP_IP, NPMODE_PASS);

        /* assign a default route through the interface if required */
        if (ipcp_wantoptions[f->unit].default_route)
                if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
                        default_route_set[f->unit] = 1;

        IPCPDEBUG((LOG_NOTICE, "local  IP address %s\n", inet_ntoa(go->ouraddr)));
        IPCPDEBUG((LOG_NOTICE, "remote IP address %s\n", inet_ntoa(ho->hisaddr)));
        if (go->dnsaddr[0]) {
                IPCPDEBUG((LOG_NOTICE, "primary   DNS address %s\n", inet_ntoa(go->dnsaddr[0])));
        }
        if (go->dnsaddr[1]) {
                IPCPDEBUG((LOG_NOTICE, "secondary DNS address %s\n", inet_ntoa(go->dnsaddr[1])));
        }
}


/*
 * ipcp_down - IPCP has gone DOWN.
 *
 * Take the IP network interface down, clear its addresses
 * and delete routes through it.
 */
static void ipcp_down(fsm *f)
{
        IPCPDEBUG((LOG_INFO, "ipcp: down\n"));
        np_down(f->unit, PPP_IP);
        sifvjcomp(f->unit, 0, 0, 0);

        sifdown(f->unit);
        ipcp_clear_addrs(f->unit);
}


/*
 * ipcp_clear_addrs() - clear the interface addresses, routes, etc.
 */
static void ipcp_clear_addrs(int unit)
{
        u32_t ouraddr, hisaddr;

        ouraddr = ipcp_gotoptions[unit].ouraddr;
        hisaddr = ipcp_hisoptions[unit].hisaddr;
        if (default_route_set[unit]) {
                cifdefaultroute(unit, ouraddr, hisaddr);
                default_route_set[unit] = 0;
        }
        cifaddr(unit, ouraddr, hisaddr);
}


/*
 * ipcp_finished - possibly shut down the lower layers.
 */
static void ipcp_finished(fsm *f)
{
        np_finished(f->unit, PPP_IP);
}

#if 0
static int ipcp_printpkt(
        u_char *p,
        int plen,
        void (*printer) (void *, char *, ...),
        void *arg
)
{
        (void)p;
        (void)plen;
        (void)printer;
        (void)arg;
        return 0;
}

/*
 * ip_active_pkt - see if this IP packet is worth bringing the link up for.
 * We don't bring the link up for IP fragments or for TCP FIN packets
 * with no data.
 */
#define IP_HDRLEN	20	/* bytes */
#define IP_OFFMASK	0x1fff
#define IPPROTO_TCP	6
#define TCP_HDRLEN	20
#define TH_FIN		0x01

/*
 * We use these macros because the IP header may be at an odd address,
 * and some compilers might use word loads to get th_off or ip_hl.
 */

#define net_short(x)	(((x)[0] << 8) + (x)[1])
#define get_iphl(x)	(((unsigned char *)(x))[0] & 0xF)
#define get_ipoff(x)	net_short((unsigned char *)(x) + 6)
#define get_ipproto(x)	(((unsigned char *)(x))[9])
#define get_tcpoff(x)	(((unsigned char *)(x))[12] >> 4)
#define get_tcpflags(x)	(((unsigned char *)(x))[13])

static int ip_active_pkt(u_char *pkt, int len)
{
        u_char *tcp;
        int hlen;

        len -= PPP_HDRLEN;
        pkt += PPP_HDRLEN;
        if (len < IP_HDRLEN)
                return 0;
        if ((get_ipoff(pkt) & IP_OFFMASK) != 0)
                return 0;
        if (get_ipproto(pkt) != IPPROTO_TCP)
                return 1;
        hlen = get_iphl(pkt) * 4;
        if (len < hlen + TCP_HDRLEN)
                return 0;
        tcp = pkt + hlen;
        if ((get_tcpflags(tcp) & TH_FIN) != 0 && len == hlen + get_tcpoff(tcp) * 4)
                return 0;
        return 1;
}
#endif

#endif /* PPP_SUPPORT */
